Conventional integrated circuits suffer from various reliability and performance issues. For deep submicron (DSM) designs, issues such as hot carrier injection (HCI), time dependant dielectric breakdown (TDDB), negative bias thermal instability (NBTI) and the like, increasingly affect performance of integrated circuits.
In order to increase the performance and reliability of an integrated circuit various operating parameters, such as the supply voltage, operating frequency, back bias (e.g., threshold voltage), and/or the like, may be adjusted. However, there is typically a tradeoff between performance and lifetime of the integrated circuit. Adjusting the operating parameters to achieve increased performance typically results in an increase in stresses, such as time dependent dielectric breakdown (TDDB). The tradeoff between performance and lifetime may be more accurately balanced if TDDB in the integrated circuit can be measured.